Multicolor coating composition and method for preparation thereof



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This invention relates to multicolor coating compositions and the methodfor preparing same.

More particularly, this invention provides an improved mottled pointcomposition which will, upon single pass application of a spray gun,provide a continuous colored base coat appearing to be interspersed witha plurality of visibly discrete particles of difierent colors, from thatof the base coat.

The invention comprises a paint latex emulsion which is normallypigmented containing microscopically dispersed interpolymers fromethylenically unsaturated monomers which as formulated are preferably,but not essentially, capable of depositing continuous films. Dispersedin visibly discrete macroscopic particles in the latex paint carrier isstill another liquid phase which is immisicible with andnon-emulsifiable in the emulsion paint latex system. The macroscopicphase is formulated generally to be of difiering hue, value, and chromaover the pigmented latex emulsion paint which serves as a suspensionmedium for the macroscopically dispersed particles or globules. Uponapplication to surfaces in films, the product of this invention providesa base coat originating primarily from the microscopicparticle-containing latex emulsion phase of one color and interspersedthroughout the base coat are a plurality of the macroscopic globules orparticles of the second liquid paint system of distinct and difierentphysical properties from that of the first or emulsion system.

This invention is bottomed upon, and an improvement over, the pioneeradvance in the protective and decorative coatings art described in US.Patent No. 2,091,466 of Busch. The compositions of Busch, when depositedin a film, provide a heterogeneous coating characterized by a pluralityof discrete macroscopic droplets of color which, by the nature of thecomposition itself and its method of application, are juxtaposed, toproduce in a single coating of material, a multicolor coatingcomposition over a previously applied base coat. Thus, Busch provided amulticolor suspension coating which, except under very specialcircumstances, required a two coat application. Other more recentpatents relating to suspension coatings of a multicolor nature arelikewise limited and require, practically, a first base coat applicationand the second coat in a second application. Included are US. 2,591,904;2,658,002; 2,795,562 and 2,809,119. British Patents 182,163 of 1922 and628,131 of 1949 also relate to the subject of this invention andsuspension coatings generally.

'In use of compositions of the prior art it is customary to mask suchportions of an area to be coated as is de-. sired to be kept free ofcoating and to follow by spraying the unmasked portion of the area witha solid base color coating material (not a multicolor coating) in orderto provide a continuous film or coating over the entire area to beprotected and decorated. The first coat provides a substrate for thesubsequently applied multicolor finish. The second coat of materialapplied has the general nature and composition as described in the priorart patents.

It is the principal object of this invention to provide a multicoloredcoating composition having all the advantages of the prior art plus theadditional advantage of States Patent elimination of separateapplication of a continuous base or substrate color coating.

More specifically, it is an object of this invention to provide amulticolor coating composition which com prises in combination a diluteaqueous solution of a protective colloid as the continuous aqueousphase, a disperse phase comprising microscopically suspended particlesof pigment and a paint latex emulsion polymer, and macroscopicallysuspended in said latex paint discrete particles of at least onecomponent comprising a viscid liquid hydrophobe coating composition,usually of varying hue, value and chroma, the vehicle solids componentof which is of such physical nature as to remain in macroscopicsuspension in the aqueous latex paint suspension in which it isincorporated without deterioration in particle size.

It is a further object of this invention to provide a method ofpreparing a multicolor coating composition capable of spray applicationto provide, in one pass, a continuous base color (substrate) coatingappearing to have interspersed therein a plurality of visibly discreteglobules, which method comprises dispersing a pigment in water,stabilizing the water-pigment dispersion with a water dispersiblehydrophilic protective colloid, fortifying the aqueous phase thereof bythe addition thereto of an emulsion polymer paint latex, and Whileslowly stirring the aforesaid microscopic aqueous dispersion, separatelyincorporating therein, in discrete order, at least one and preferably, aplurality of visibly separate globules of a hydrophobic pigmented liquidcoating composition, the vehicle solids of which are characterized bytheir physical property of non-emulsifiability in the system and whichremain in suspension in visible macroscopic particles in said aqueouscarrier system.

=It is a further primary object of this invention to provide animprovement over the prior art, which permits ready application of amulticolored mottled paint composition and a corresponding solid coloredsubstrate'or base coating therewith by single pass of a spray gun.

These and other objects of the invention will be more fully developed asthe description of the invention proceeds.

The art of reference discloses that one may produce a multicolor coatingcomposition by first preparing a dilute solution of an aqueousprotective colloid and slowly stirring into the prepared aqueoussolution, sequentially and in discrete fashion, a plurality ofrelatively heavy-bodied colored coating compositions of generallyhydro-phobic nature, including paints, varnishes, lacquers and enamelsand these non-selectively.

In the prior art, multicolor compositions one may use colored enamels,lacquers, etc., as they are sold through retail establishments, and byadding these separately with slow agitation to aqueous systemscontaining dispersed therein a wide variety of protective colloids, itis possible to produce a liquid material which can be applied by spraygun to deposit in macroscopic form, globules of the various coloredpaints which, because of the protective colloid in the aqueous phase, donot blend with one another.

In the prior art coatings, as described and identified above, it ismandatory to avoid the presence of surface active agents. tial as theirpresence would cause a size of the macroscopically suspended paintcoatings to microscopic dimension (form an emulsion) and thereafter theresultant coating composition would perform similar to a resin-emulsionpaint.

Latex emulsion paints, as known, all contain surface active agents whichare essential to the end of manufacture, storage and use of theseproducts. If one attempts to disperse the liquid macroscopic particlesof vehicles as used in prior art suspension paints in aqueous suspensionAvoidance of surface active agents is essen-- breakdown in particle inaccordance with the present invention, the macroscopic particles orglobules break down in size and emulsify when the coating is vigorouslyagitated, as usual in manufactune, or in application of paint by meansof spray gun techniques. Thus non-selectively, paints, varnishes,enamels and lacquers operatively useful in the. prior art are inoperablefor purposes of the present invention.

The one-coat multicolor coating compositions of this invention areprepared in general as follows: An aqueous solution of a. protectivecolloid is prepared by dispersing from about one-half to less than aboutof a protective colloid in water. The amountdepend's upon. theprotective colloid selected. As is standard practice small amounts ofpreservatives, illustratively the alkali metal salts of polychlorinatedphenols are dissolved in the aqueous protective colloid solution.Pigments essential to hiding; quality and to gloss level control in thefinal product are dispersed in water or in the aqueous protectivecolloid solution by initial mixing and later subjecting to a zone ofhigh shearing stress as may be provided by a Cowles dissolver,pebble-mill, Hy-R-Speed Mill, Premier Colloid Mill or other equivalentshearing device used in pigment dispersion. If not previously combined,the dispersed pigment slurry andaqueous colloid dispersion are combined.The quality and amount of pigment present may be varied widely, or mayin some unusual cases be omitted entirely. The amount and kind ofpigment will varydepending upon the hiding quality of the particularpigment chosen, the shade or depth of color and the degree or quality ofgloss wanted. These are factors understood. by those skilled. in thepaint art.

Tothis slurry is added a quantity of an emulsion interpolymer,preferably an interpolymer of ethylenically unsaturatedmonomers'polymerized in an emulsion system as are commonlysoldcommercially for use in the manu-. facture of latex emulsion paints.The emulsion polymer particles are of microscopic particle size and. theemulsions of the. class of interest are herein referred to from time to.time. as paint latices or paint latexes. It is. preferred to. use acopolymer of an'aromatic monovinyl hydrocarbon having a single center ofunsaturation and conjugated. diolefine, wherein the proportions of themonovinyl hydrocarbon donot exceed. 67 mol percent and the diolefinedoes not exceed 60 mol percent as. the. ethylenically unsaturatedmonomers in the: paint latex emulsion. Present preference is not,however, to be. 'construed' as limiting. Other emulsion interpolymerlatices are being continuously introduced for paint-making purposes andsubstitution of latex emulsions which are substantially-equivalent isanticipated. Other paint latices maybe substituted therefore, as will:be discussed herein more fully, and are substantial equivalents to thepaint latex named as far as operativeness of the invention is concerned.Obviously, some paint latices are more. usefulthan others for reasonshaving no relation to the present invention.

It is well known that emulsion interpolymers of ethylenic'all-yunsaturated monomers are usually manufactured by emulsion polymerizationin an aqueous system containing protective colloids, free-radicalcatalysts: and normally surface active agents of non-ionic oranionicchara cter. Surface active agents normally present in paint analiphatic.

latex emulsion interpolymers in the quantities normally and inherentlypresent in the latex emulsion systems may be. carried into the paintsystems which constitute this invention without difficulty. The smallamounts of surface active agents thus carried in do not interfere withthe general objects of the invention. From time to time. it may be founddesirable, when the combination of ingredients produce paints within thepurview of this invention and which lack the requisite emulsionstability, which sometimes occurs with certain pigments when incombination with. particular emulsion copolymer paint latex systems,

a small amount of a non-ionic polyoxy alkylene polyether alcohol surfaceactive agent, may be added to the system and is often salutary.

Compounds known to cause particular dificulty when present ascontaminants or included for one reason or another in one or more of theessential components of the invention, are. the polyphosphate salts.Illustratively, sodium hexametaphosphate, potassium tetrapyrophosphate,sodium sulphate and other strongly ionizable inorganic salts are theWorst offenders and should be completely avoided wherever possible.

The pigmented. varnish vehicles used to form the macro scopic phase arelimited to those varnish vehicles whose vehicle solids and whose organicsolventreduced vehicle solids or final varnish can'he identified ashaving at least one HN value below 60. The pigmented macroscopic phaseis prepared by grinding colored pigments into the varnish vehicle by theusual paint techniques. It is customary and usual that the vehiclesolids of varnishes having the proper HN requirement be reduced withvolatile organic solvents in order that handling may be made easier.Where possible it is referred to use aliphatic solvents as it has beenfound that the nature of the solvent has some efiect upon thecleanliness and brilliance of the macroscopic globule of vari-coloredcomponents in the dried film. Aliphatic solvents are more favorable to aclean and unsullied macroscopic phase particle than when aromaticsolvents are present. The use of aliphatic solvents has been found toprovide greater latitude in the selection of protective colloidsincorporated into the overall paint system. When aliphatic solvents. areused in thinning the varnish solids, there is no need for selectivityfrom among all .of the known protective colloids, representativeones ofwhich have been tested. If one finds it essential to use aromaticsolvents, illustratively toluene and xylene, as is. necessary inreducing certain qualitiesv of varnish solids, illustrativelyvarnishesof the glycidyl ether type, then. in those cases it is preferred to usethe Water soluble cellulose ethers as the protective colloid. It, has.been found by following this practice that no difficul'ty is thenexperienced with clouding of the spatter color or macroscopic globules.of vari-col'ored material. in the final paint film. It has. been foundthat solvent. selection is of material significance or the dispersedmacroscopic pattern tends. to be overgrown with the pigmented baseemulsion. latex material. Aromatic solvents. have also been found to begenerally detrimental to the freeze-thaw resistance of they suspensionpaints of this in vention when stored in. unheated warehouses.Comparative tests. have shown aliphatic solvents also superior for the.purposes or" resistance to freeze-thaw breakdown as compared with thearomatic solvents under similar test conditions.

Driers and dryingpromoters, anti-skinning agents and others commonlyused in the paint art may also be added to the liquid macroscopic phaseeither before or after grinding in the pigments as is well. known in thepaint art. It is preferred to maintain the solids and. the viscosity ofthe macroscopic phase of the paint system of this invention atrelatively high levels. By so doing the final coatings are obtainedhaving a more pleasing optical response. If the macroscopic phasevarnish vehicle is overly thin (e.g;v too much volatile solvent or notof suflicient' viscosity) the plural colored pattern is apt to diminishin particle size and to be so fine as to lack character.

The aqueous slurry comprising the latex emulsion, pigment and protectivecolloid as. prepared above. is slowly agitated while measured amounts.of the pigment-varnish system of hydrophobic nature. as prepared. are.stirred, in sequence and oneat a. time in discrete order, into theaqueous latex emulsion paint system under agitation. Colors may also beboxed after suspension in water, as is known, before addition.

One color maybe used, or a series of. colors to furnish a: plurality ofmacroscopic, discrete hydrophobic particles of liquid color suspended inthe aqueous base. Alternatively, separate portions of the aqueousemulsion base may be measured out, each mixed with a single addition ofthe macroscopic hydrophobe particles of liquid color, and after stirringeach one to a desired particle size, the individual ones of the preparedsuspension may be boxed together to produce an infinite variety of coloreffects.

As can be seen from the above description, improved multicolor coatingcompositions are produced with relative simplicity. Quantities of theessential components can be mixed in a wide variety of proportions. Thequantities of the various components are not particularly critical, dueregard being shown the general qualities essential to an operable paintsystem such as viscosity, weight per gallon, density, etc., commonlyknown to be of importance in the paint art and which qualities areapparent especially to one skilled in the emulsion paintmaking field.There has been described above, generally, a method of manufacture ofimproved mottled coating compositions which dispenses with the necessityof separate application of a base color coat.

Having thus described the method of reduction to practice of theinvention in general, detailed attention will be given to the questionof differentiation between operable and inoperable components within theframework of the descriptive term used and the question of substantialequivalency among the sub-classes of those classes of viscid hydrophobicvarnish materials which are essential to the ends of this invention.

THE HYDROlHOBIC VARNISH PHASE In the greatest measure this inventionrests upon the discovery that drying oils and varnishes in common use inthe protective coatings field vary Within extremely wide limits as to aphysical quality, herein referred to as the Hydrophile-Lipophile Balanceor HLB; or Hydrophilic Number or H It has been found to be possible bycareful attention to this little known quality to avail oneself ofvarnishes which will not emulsify in aqueous emulsions of ethylenicallyunsaturated monomers in polymeric form as does occur with othervarnishes which may be of apparently similar chemical origin but ofdifferent physical-chemical surface properties.

Through discovery of the existance of varnishes which will not emulsifyin latex paint systems, it is now made possible to produce a hybridcoating having all the advantage of the popular latex paints, namely;ease of ap plication, high-hiding quality, freedom from fire hazard andpleasing pastel colors at minimum costs plus the tremendously widevariation in color combinations and optical differences potential in thesuspension systems as derive from Busch in a coating composition whichcan be applied to surface with the further economy of but a single coatapplication.

As indicated, the most important element of the present invention is thesuspension varnish vehicle. Useful varnish vehicles are identified andseparated from all non-useful varnish vehicles by a particular physicalquality which is referred to as the Hydrophilic Number requirement orbriefly, HN requirement. The same quality is also identifiable by amathematically related concept which is referred to as theHydrophile-Lipophile- Balance or HLB requirement of the vehicle. Workersin the field correlate these two concepts for most practical purposes inaccordance with the following simple equation: HN=5HLB.

For those who wish to review the subject of this physical quality andfor purposes of illustration and clarification, the following articlesare included herein by reference the same as though they were set forthherein in their entirety.

(l) Classification of Surface Active Agents, volume 1, No. 5, December1949, and (2) Calculation of HLB Values of Non-Ionic Surfactants, volume5, No. 4, December 1954.

mid-point of the range. Another group, concerned These first twoarticles are found in issues of the flournal of the Society of CosmeticChemists in articles by Wm. C. Griflin.

(3) Clues to Surfactant Selection Offered by the HLB System, OfficialDigest of the Federation of Paint and Varnish Production Clubs, June1956, by the same author.

(4) The commercial booklet entitled Igepals, published by AntaraChemicals, 435 Hudson Street, New York 14, N.Y., in March 1954.

The experimental method for determining the HLB requirements, or HNrequirements, of a given hydrophobe are described in the referencesabove. However, a short description of the method for its determinationfollows, using the symbols HN to identify the concept.

To determine the HN value of a varnish hydrophobe one may wish to employin the compositions of this invention, the following procedure issuggested. The varnish (resin or oil) phase solids to be evaluated forsuitability as a component of the macroscopic phase of the coatingsystem is diluted with a suitable volatile organic solvent whose I-INvalue is known or has been determined by a similar test to the one whichfollows. The percentage of vehicle solids and volatile solvent isrecorded. A series of tall slender bottles (olive jars will do) arelined up and 48 grams of the prepared oil phase of unknown HN areweighed into each jar. Three grams of each one of a series of non-ionicsurfactants of varying and known HN value are individually weighed intoseparate ones of the test jars and the HN value of the surfactantweighed and recorded on the jar corresponding. The emulsifiers arestirred into the hydrophobe and 72 grams of water added to eachspecimen. The jars are shaken vigorously and uniformly for thirtyseconds and allowed to rest for 5 minutes, whereupon the shaking isrepeated for several 30 second intervals. If after 24 hours rest it isnot clear which HN number applies to the vehicle (by selection of thebest emulsion among the series) the samples are re-shaken and a week isallowed to elapse. Usually this time is sufiicient to indicate the HNvalue of the mixture of hydrophobe solids and volatile organic solventtherefor. This value is noted. In more accurate determinations in closeor stubborn cases where phase resolution is slow the test may be carriedon over a month or more period.

The HN requirements of the hydrophobe solids are determined by simplecalculation in accordance with the following. Assume that xylene wasused as the solvent (HN of xylene=57) to produce a 50% vehicle solidssolution of the test resin. An HN value of a typical test HN requirementof a useful varnish hydrophobe for the present purpose Was found to be54. If X is equal to the HN of the hydrophobe oil solids, Y is equal tothe HN of the solvent and Z is equal to the HN of the resinsolventmixture; the following equation can be set up:

=50X-27OO 50X: 150

Briefly stated the HLB or HN value is an expression of the relativesimultaneous attraction of an emulsifier for water and for oil (or forthe two phases of a system to be emulsified) For purposes of conveniencethe.

effective balance of these two groups is assigned a numerical value.Under the HLB system of nomenclature those surfactants most lipophilic(or attracted to oil) are given low numbers and those attracted stronglyto Water are assigned progressively high numbers. The numerical valuesrange from one to forty with 10 being a practical with non-ionicsurfactants have adopted the term Hydrophilic Number, or HN to theconcept. The HN value in early work was determined to be equivalent tothe weight percentage of ethylene oxide groups in the total non-ionicmolecule. This has been established only for non-ionic agents having analkyl phenol nucleus. Thus, non-ionic surface active agents having analkyl substituted phenol nucleus, an HN of 50 (HLB of has 50% ofethylene oxide groups by weight in the total molecular weight of thesurfactant.

Further experience with assignment of numerical physical constants toemulsifiers has established that these values are not limited toethylene oxide containing surfactants, nor to any particular chemicalclass of emulsifiers but can be assigned to anionic surfactants as well.For example, the well-known sodium salt of dioctyl ester ofsulfosuccinic acid (Aerosol OT) has been demonstrated to have a veryhigh Hydrophilic Number. Part of the higher values attributed to thisclass is believed due to their ionic nature. Indications are that thecationic agents are also of very high HN.

A further useful extension of the physical constant referred to hereinas Hydrophilic Number or HN is that such number may be assigned equallyas well to hydrophobe substances which form the oil phase of emulsionsystems. Thus, the oil phase of an emulsion system may be said to havean HN requirement of 20, 32, 50 or 85 as illustrative of a commonnumerical range. The HN requirement may be different for the samevehicle depending upon the type of emulsion one wishes to produce, e.g.whether oil-in-water or water-in-oil emulsions are desired.

In this specification, by election, reference is to the HN requirementfor oil-in-Water emulsification. This invention is not primarilyconcerned with the production of emulsions, although a paint latexemulsion system is an essential component of the coating compositionsherein described and claimed. It has been found that the essentialhydrophobe component of the invention can be accurately defined by HNrequirement, the physical constant described above and which isapplicable to varnishes in general use.

From the above it is believed clear the meaning of the term HNrequirement and the fact that the numerical designation of a varnishvehicle as a particular HN has relation to a physical propertyidentifying the surface characteristics of varnish vehicles.

In the parent application, U.S. Serial No. 538,283, filed October 3,1955, now abandoned, and from the data then available it was believedonly vehicles having an HN in excess of 105 were useful. The species ofvarnish vehicles first used in reduction to practice of the inventionand for the present invention were of the class commonly referred to asepoxides or more completely identified as glycidyl polyethers ofdihydric phenols, free from functional groups other than epoxy andhydroxyl groups, having an epoxy equivalent greater than one whencalculated on a 100% solids basis; and the drying oil fatty acid estersof these epoxide vehicles. Original HN determinations indicated thatthese vehicles had values above 105 and the varnish vehicles sodescribed were determined to be in the 110 to 130 range of HN value.

In subsequent determinations of the HN of several of these epoxy resinvarnishes, as well as additional varnish vehicles it was found that thehigher values of HN were not as clear and definite over longer testperiods and under more accurate tests as a second value of HN found forthese vehicles which existed in a range of 50-55. These markedlydifferent secondary values were originally observed in testing theepoxide varnishes which checked out in the original range of HN valuenamely from 110 'to 130. Re-checking of the determinations after severalweeks additional test time of storage verified the values in the lowerrange were of greater accuracy than the higher values and of morecertain reproducibility.

In order to provide this disclosure and application with furtherexamples of operable vehicles having HN'values within the operablerange, a representative group of varnish vehicles from thoseinproduction and commercial use were obtained. The Hydrophile Number ofthe solvents used with those'varnish vehicles was known as well as thepercentage of non-volatile vehicle solids used to make the varnishes wasalso known. The HN numbers of this representative group of varnishes wasthen determined, based on' varnish vehicle'solids content. This samegroup of varnishes were used in trials to determine their operability inthe products herein described. There was complete substantiation of theconcept that the HN value of the varnish solids defined operable speciesfrom those which were inoperable. It was also established that no knownmethod of definition by chemical compositions separated the knownoperable varnish systems from the known inoperable varnish systems. Theuseful varnishes, their composition and manufacture are described morefully in the examples which follow. It was found that above an HN of 59,as shown in Example Vehicle #24, a definitely borderline varnish vehiclewould be obtained (unless a second HN requirement of the varnish vehicleexceeded All varnish vehicles having one HN below 59 and those showing asecondary value above 110 were operable. Varnish vehicles having but asingle determinable HN value in the range of 104-106 were found to beinoperable for the purposes of the in vention. There were no varnishes,other than the epoxide varnishes, found having the high HN value above110 in the great number tested. Useful varnish vehicles solids having anHN value of less than 59 and down to a value of 26 (the lowest valuefound) were tested in formulations and all were operable for thepurposes of the invention. A range of HN from 50 to 58 was preferred andencompassed the most useful varnish vehicles those varnishes whose HNcould be determined.

As far as is known, there is no problem involved in changing of thevehicle solids content of the varnishes useful for the purposes of thepresent invention. Changes are made in the solids content of thevarnishes by adding or withholding solvent. Most, if not all, of thevolatile organic solvents standardly used to thin varnish solids to arequired viscosity level have HN requirements of below 59. Thus, if thevehicle solids have an HN requirement below 59 and the solvent is alsoof HN requirement below 59, changing the percentage of vehicle solidswill not adversely change the HN requirement of the result-ant vehicle.Varnish vehicle as used herein may, therefore, be at any solid-s leveldesired so long as the HN requirement of the solvent reduced varnish isbelow about 60.

Of all the varnish vehicles subjected to evaluation from commerciallyavailable sources only two were indeterminate in relation to HN value.Of these, one was a black asphaltum varnish, which because of the color,could only be estimated as to HN value. The asphaltum material wasestimated to possess an HN requirement of 26, which was the lowest ofall ve 'cles subjected to HN determination, and upon check out at thisvalue good emulsion products were obtained confirming the estimatedvalue to be accurate.

The second vehicle which was found particularly useful for the purposesof the invention but which was indeterminate as to its HN requirement isa polyamide resin of strongly thixotropic physical nature having agellike physical structure. This varnish is often referred to in thepaint art as a Burnok or Washburn vehicle. Because of the unusualphysical nature of this varnish vehicle it is well known in the art andisof a highly specialized class. The polyamide resin of indeterminate HNrequirement is more fully described in the Winkler patent, US.2,663,649, and an essentialcomponent thereof is described in US.2,450,940, both of which patents are incorporated herein .by reference.

The Burnok or Washburn varnish vehicle is of indeterminate HydrophileNumber or HN and found to be very useful in the invention is notclassifiable in accordance with its HN value as are all the otheroperable varnish vehicles useful in the compositions of this invention.Oddly enough, considering the nature of the Burnok varnish it is mineralspirits soluble. It is one of the few vehicles known among the polyamideclass to be soluble in mineral spirits and the only well-known vehiclehaving extremely marked thixotropic quality. A great number of attemptsto determine the HN number of this vehicle have proved inconclusive. Ithas been found to be iudeterminant as to its HN number, that is, the HNnumber could not be determined by the tests applicable to othervarnishes.

The Winkler or Burnok polyamide resins are, in turn, prepared byreaction of the polyamide resins of Cowan et al., described in U.S.Patent 2,450,940 of October 12, 1948, with modified solvent solubleoleoresinous varnish esters.

oleoresinous varnishes, as the term is used herein, include thosedefined by Mattiello, volume 3, pages 194 and 195, and the members ofthe class as defined on page 195. All comprise the unsaturated dryingoil fatty acid esters of polyhydn'c alcohols, some of which contain inaddition dicarboxylic acids to form complex polyesters.

For the purposes of identification, the Winkler polyamide resins may bereferred to as mineral spirits soluble fatty acid oleoresinous varnishester-polyamide condensation of molecular weight between 3000 and 9000.This language is herein intended to identify the solvent dispersiblepolyamides corresponding to those described and claimed in U.S.2,663,649.

A more complete but lengthy definition in essence synonomous with theabove is a mineral spirits soluble polyamide resin which polyamide resinis the reaction product of polymerized unsaturated fatty acids with analkylene polyamine having two to four amine substituents and theinteresterification product of an oleoresinous ester varnish comprisingthe condensation of an unsaturated fatty acid, a polycarboxylic acid anda polyhydric alcohol, the said interpolymer reaction completed at a temperature above the melting point of said polyamide resin but below 600F. of molecular weight between 3000 and 9000. Manufacture and use of avarnish vehicle of this class is also illustrated in the illustrativeexamples which follow.

THE PROTECTIVE COLLOID A second essential component of the presentinvention is the protective colloid. While it is preferred to use one ofthe water soluble alkyl cellulose ethers as the protective colloid, asthe members of this group allow maximum freedom in formulation insuspension paints within the scope of the present invention in general,all the commonly used protective colloids may be successfully employedwith due care for other factors being exercised as noted more fullyherein.

The term protective colloid is a well understood term of art. Ingeneral, protective colloids used in aqueous emulsion systems areidentifiable by their physical colloidal behavior rather than theirchemical nature. In general protective colloids are known to increasethe viscosity of aqueous systems in which they are dispersed indisproportionately great amount relative to the quantity of the colloiddispersed in water. Other terms used to describe protective colloidsinclude suspension agents, stabilizing agents, protective agents,stabilizing colloids, etc., but the term protective colloid is believedmore apt and to be in accordance with art accepted usage.

Historically, the inorganic protective colloid, bentonite clay, wasprobably first used for its protective colloidal value. The naturaloccurring organic protective colloids were, no doubt, next in chronologyand include agaragar, Irish moss, gum arabic, albumen, gelatin, starch,alginates, etc., Casein and the vegetable proteins includl0 ing cornprotein and soya bean protein have been and are now extensively used inthe emulsion paint art, though they appear to be losing some ground tothe relatively recent synthetic hydrophilic protective colloids, oneprincipal group of which include the water dispersible (colloidallywater soluble) modified celluloses. Among this latter group and thosepreferred for the purposes of this invention are methyl cellulose, watersoluble ether cellulose, methyl-ethyl cellulose, hydroxy ethylcellulose, sodium cellulose glycollate, and carboxy methyl cellulose.

The preferred group includes methyl cellulose which contains between 1.2and 1.9 methoxy groups per anhydroglucose unit; water soluble ethylcellulose which contains between 0.8 and 1.3 ethoxy groups per glucoseunit; and methyl-ethyl cellulose which contains from 0.3 to about 0.5methoxy groups and 0.8 to 1.0 ethoxy groups per glucose unit. In theforegoing water soluble cellulose derivatives, a variety of viscositygrades are available and useful in the present invention. In general,the higher the viscosity grade, the less the original degradation of thecellulose molecule prior to etherification.

Still another class of protective colloids useful for the purposes ofthe present invention and now used to some extent in the latex emulsionpaint art are water dispersible high polymer including as illustrativesodium polyacrylate, ammonium polyacrylate, etc.

In the first reductions to practice of the present invention asdescribed in U.S. Serial No. 538,283 (of which this application is acontinuation-in-part), aromatic solvents were used to reduce theviscosity of the epoxy varnishes which constituted the macroscopicdisperse phase of the multicolor coatings of the invention. It was foundthat when aromatic solvents were so used, the water soluble alkylcellulose ethers were the only protective colloids which allowed fulland clean color development in the dried film of the macroscopicdispersed phase particles. However, it is known that the operablevarnish resins need not always be reduced with aromatic solvents.Aliphatic solvents are useful in the case of many of the operablevarnish resins, and with use of aliphatic solvents it is now bothfeasible and practical to use any one or combinations of more than oneof the water dispersible protective colloids as heretofore described andas are commonly employed in the art of paint latex emulsion manufacture.Thus, by and through solvent control in the varnish, one may adapt touse in the present invention any one of the prior art protectivecolloids, albeit, some are more useful and preferred over others.

The amount of the protective colloid used is sufiicient to preventemulsion breakdown of the microscopic phase and the ranges of percentagelie between about 0.5% for sodium acrylate, for example, and somethingless than about 20% for the vegetable proteins by weight of the aqueousphase. Thus the quantity of protective colloid useful and essential willdepend upon the quality of the protective colloid selected.

If one attempts to carry into combination a pigmented latex emulsionpaint and macroscopic discrete particles of variously colored liquidhydrophobic varnish coatings as previously described in the suspensionpaint art to produce multicolor paint globules of hydrophobe color, saidparticles are rapidly reduced in size due to the combined action of theemulsifying agents and the protective colloids present in latex emulsionpaints. It has been found that the quality of the viscid liquidhydrophobe of the macroscopic part of the coating must be selected tohave a particular physical property for the invention to be operative.

When the added discrete particles are thus reduced in size belowvisibility to the naked eye, obvious heterogeneity of the system is lostand the desired color differences dissipated. This happens rapidly uponattempting to spray apply coatings not within the scope of thisinvention as from a spray gun. It is well known, for example, thatpigments added directly to emulsion polymer latex systems causeaggregation of the emulsion particles and further reduction of thequantity of the protective colloid leads to emulsion polymer breakdown.Thus the presence of protective colloid is essential. In order toovercome breakdown of emulsions upon application, prior art emulsionpaints employ dispersions of aqueous proteins as efiiective andeflicient protective colloids. Anionic and non-ionic wetting of surfaceactive agents; for example, sodium alkyl aryl sulfonates areillustrative of the first class and alkyl aryl polyoxyalkyline alcoholsare illustrative of the second class; are also incorporated to obtainnecessary emulsion paint stability.

As previously observed inorganic dispersants, such as the water solublepolyphosphates (usually present in latex emulsion paints), are adetrimental factor and interfere with maintenance of macroscopic colorglobules in suspension.

While it is not intended to be bound by theory, it is believed that theherein described alkyl cellulose ethers are unique among organicprotective colloids in that they tend to decrease the surface tension ofwater less than most additives to aqueous solutions. While his nowreported that a 1% solution of methyl cellulose has a surface tension of47-5 6 dynes, prior personal experience has indicated but little changein surface tension upon addition of methyl cellulose to pure water (e.g.72 dynes/cm.) Most other organic protective colloids, in common use inwater reducible emulsion paint systems, decrease surface tension and actof themselves as emulsifying agents as well as protective colloids.Thus, while the emulsion polymer systems carry into the coatings of thisinvention objectionable surface tension depressants and emulsifiers, thesingular quality of water soluble alkyl cellulose ethers as a class tendto counterbalance rather than to assist adverse efiects of theemulsifying agents used in emulsion polymerization (in which paintlatices originate) and thus are a preferred class of protectivecolloids. Alkyl cellulose ethers permit macroscopic globules ofhydrophobic coating compositions containing aromatic solvents to remainrelatively constant in particle. size in suspension in the system.Macroscopic color particles are visible in the bulk coating as well asin the films deposited from spray application. Further, watersolublealkyl celluloses described are effective to protect the paintlatex polymer emulsion from emulsion breakdown upon pigment addition andupon freeze-thaw cycling.

EMULSION INTERPOLYMERS OR PAINT LATEX A third essential component of thepresent invention is an emulsion interpolymer paint latex. For thepurposes of the present invention all commercially available paintlatices or latexes have been tried and found operable. All known. paintlatexes have been produced from ethylenically unsaturated monomers byemulsion polymerization techniques. The possible permutation andcombination of ethylenically unsaturated monomers in combination ashomopolymers, copolymers and terpolymers is legend. It is impossible todescribe completely by purely chemical concept the scope of usefulemulsion polymers as it is the physical behavior and quality of theemulsion polymers from ethylenically unsaturated monomers rather thantheir individual chemical constituents which separates the useful fromthe non-useful film-forming emulsion latices.

A straight polystyrene emulsion polymer is useful, for all intents andpurposes, for practice of the present invention. It is not a desirableselection, however, for reasons which are outside the scope of thepresent invention combination. It is not desirable because of inferiorfilms which it forms. Polystyrene emulsion homopolymers are operative toproduce multicolor paints as is the object of the present invention. Thepaints so made are not desirable, however, as they lack other qualitieswhich are sought for in a practical paint system which will continue toenjoy commercial acceptance. These factors, as indicated, are outsidethe scope of the present invention but of extremely practicalsignificance in the selection of the paint latex.

Paint latices and latex emulsion polymers capable of depositingcontinuous stet films are an outgrowth of a study of the art ofproducing polymeric bodies from monomers of aromatic vinyl compoundshaving a single center of unsaturation (e.g., styrene) and conjugateddiolefines (e.g., butadiene). The initial objective of study of emulsionpolymerization was production of synthetic rubber in massive form.Original emulsion products intended as paint latices contained styreneand butadiene in reverse ratio or reverse proportion to the ratios usedin massive synthetic rubber and for this reason are labeled as reverserubber" latices as a common term of reference. The preferred paintlatices for the purposes of this invention are copolymers andterpolymers comprising monovinyl aromatic hydrocarbons and aliphaticconjugated diolefine containing not more than 67 mol percent of themonovinyl aromatic hydrocarbon and not more than .60 mol percent of thealiphatic conjugated diolefine. Terpolymers may include the lower alkylacrylates, including methyl and ethyl acrylate monomers as well asvinylidene monomers, all of which are ethylenically unsaturatedmonomers, as starting materials in emulsion interpolymer formation.

While useful and preferred paint latices are found in the class justdescribed, other homopolymers, copolymers and terpolymers in emulsionform useful as paint latices are in commercial production, commonly soldfor use in emulsion paint systems and are more or less equivalent forthe purposes of this invention. These emulsion polymers include vinylacetate latex, vinyl acetate-vinyl alcohol emulsion copolymers, vinyl'acetate-dibutyl maleate copolymers, homopolymers of methyl acrylate andethyl acrylate, emulsion homopolymers of polybutadiene, etc.Illustrative U.S. patents describing paint latices include U.S.2,536,470; 2,676,930; 2,498,712; 2,476,967; 2,683,- 699; 2,683,700 and2,771,456, which, disclosures are included herein by reference as a partof the paint latex art.

As previously indicated, and in the light of the above, it can be seenthat there is little correlation in setting forth the chemical names ofmonomers useful in producing paint latices by emulsion polymerization.However, the paint-useful emulsion polymers can be defined in relationto their physical qualities and properties, and in their method ofmanufacture.

Without exception the monomeric materials are polymerized in dispersedmicroscopic form in an aqueous carrier in the presence of surface activeagents and polymerization promoting free radical catalysts. Thedispersed phase interpolymer particles have molecular weights which arerelatively large multiples of the molecular weight of the simplemonomers from which they are formed or derived. The solids content (ornonvolatile) of the useful emulsion polymers is of the order of 50%. Asfar as has been known or ascertained all of these interpolymer solidsare possessed of an HN requirement of more than 70 and less than about90.

When spread out in thin films, either alone or in the presence ofplasticizers and solvents incorporated into the emulsion system, andallowed to dry, the disperse polymeric phase preferably coalesces toform a continuous, coherent film possessed of such film integrity as toresist re-dispersive action of soap and Water. Paint latices are furthercharacterized by having film-forming and pigment binding quality. Suchcoherent films are herein referred to as stet films. A stet film isequivalent in general properties to the film resulting from paints andvarnishes after solvent evaporation, oxidation and polymerization, orlacquers after evaporation of solvent.

Straight polystyrene emulsions, for example, do not deposit stet films;for unless plasticized their films deposit 13 out like beads and arelacking in cohesiveness and film integrity essential to paint usage.

The particle diameter of the disperse organic polymer phase is ofmicroscopic order. Non-settling of the disperse phase is a universalquality. Unless specifically fortified by additives, or by extreme skillin formulating the emulsion copolymer, paint latices are susceptible tophase separation and emulsion breakdown upon repeated cycles of freezingand thawing. Additives are known which prevent coalescence due to thiscause and are neither excluded from nor included in presentconsiderations. (See US. Patents 2,683,699 and 2,683,700 for suchadditives.)

The term macroscopic as used herein is opposed to microscopic and refersto particles which are large enough to be seen without the aid ofoptical systems by one having normal vision. Macroscopic particles areintended to exclude the microscopic particles found in emulsion systemsand include particles of at least of an inch in diameter upwards.Particles at least as large as A of an inch in diameter are notuncommon. Useful pigmentary materials may be as small as 1 micron andnot generally larger than will pass through a 325 mesh standard sieve.Thus they are of microscopic range of particle size.

The above exposition is intended to make clear the metes and bounds ofpaint latex materials useful and substantially equivalent to componentsherein specifically illustrated and described as essential. Many of thedetails ofmethods of preparation of the individual components of thisinvention are more fully described in the literature and are a part ofthe heritage of the art.

While it is believed that the scope and order of this invention has beenmade clear from the above description to accord with patentrequirements, the following formulas and examples are included asexemplary of methods of reducing the invention to practice. All parts ofthe following examples are by weight unless otherwise stated.

Example 1 In a five liter flask equipped with heater, agitator,thermometer and reflex condenser heat 912 parts by weight of his phenoland 465 parts by weight of epichlorohydrin to ISO-160 F. Holding thetemperatures relatively constant at this level, add 1600 parts 20%aqueous caustic soda slowly over a time period. Continue to hold thetemperature at ISO-160 F. for one hour after all the aqueous caustic hasbeen added. Cut off the heat and recover the taffy colored mass from theaqueous phase which separate upon standing. The resinous mass is waterwashed until salt free and the occluded water present in the resindistilled off.

The HN value of the resin solids was determined to be above 105 (110)(not rechecked subsequent to the filing of the parent application). Theresin when out with a high Kauri-butanol value aromatic naphtha to 50%solids proved useful, when pigmented, as the macroscopic phase in thepresent composition. 'However, upon esterifying the resin, as in Example2, with drying oil fatty acids over-all performance in paint systems ofthis invention were improved.

Example 2 60 parts of the resin of Example 1 were heated to 480 F. with400 parts dehydrated castor fatty acids and held to an acid value offrom 12. The resulting ester was cut to 50% solids with a high boilingnaphtha having aKauri-butanol value above 90. The HN of the solids wasfound to be 117. Later tests indicate a more accurate determination tobe at a HN requirement of 51. The 117 value is now believed to be asecondary value and less accurate than obtained with repeated checksunder more reproducible controls made subsequent to the filing of theparent application herein identified.

14 Example 3 450 parts by weight of the ester of Example 2 250 partsCaCO -silica pigment (Lorite) 20 parts molybdate orange partsdiatomaceous earth (Celite) 2%. parts 4% lead drier Vs parts 6% cobaltdrier parts 6% manganese drier were mixed to'a smooth paste and groundover a three roller mill. The mill output was thinned by addition of:

100 parts ester of Example 2 p 108 parts high flash naphtha ofKauri-butanol value of 90.

This formed .a viscid hydrophobe pigmented varnish orange base useful asthe macroscopic phase of the invention. Example 4 Same as Example 3, but5 parts of phthalocyanine green replaced the 20 parts of molybdateorange in the pigment.

Example 5 Same as Example 3, but 5 parts phthalocyanine blue replacedthe 20 parts of molybdate orange.

Example 6 Into a change can mixer were weighed the following ingredientswith continuous agitation of the mixer.

225 parts water 200 parts titanium dioxide 2 parts black iron oxide 25parts CaCO -silica pigment (Lorite) heat to F. and add:

6 parts high, gel methyl cellulose 4000 cps. grade and mix for 10-15minutes. Add 225 parts ice water and cool to room temperature or below,add:

To 250 parts by weight of the base of Example 6 were added, while thebase was being stirred slowly, 75 parts of the orange pigment paste ofExample 3 and later and separately 25 parts of the blue paste of Example5. Macroscopic particles of these colors were thereby suspended invisible or macroscopic globules in the emulsion base. Upon spraying outa sample of the composition with one pass of the spray gun, a grey basecoat was deposited on the panel with a superimposed or interspersedspatter coat of visibly large particles of orange and blue paste, someof which particles were in juxtaposition relative to one another.

1 Example 8 Example 10 To 250 parts of the aqueous base of Example 9were added 50 parts of the hydrophobe varnish-pigment green solidsubstrate. coat was obtained with but a single pass of the spray gunupon applying the resultant suspension in a thin film for coatingpurposes. The material dried to produce a washable film after overnightdry.

Example 11 Similar to Example 6, but the 235 parts of styrenebutadienepaint latex emulsion were replaced with 245 partsof 45% vehicle solidsemulsion polymer of acrylonitrile (Rohm & Haas AC33). No diflicultieswere experienced, either in formulation or in application of the productupon stirring in representative amounts of the color bases of Examples 4and 3. No appreciable emulsification of the macroscopic disperse phaseoccurred upon spray application. One pass of the gun upon sprayingproduced a base coat of solid color, over-layed with a visiblespatter-pattern coating. The. dried film had good washability after 48hours of drying time.

Example 12 Same as Example 6, but the 235 parts of the styrenebutadieneemulsion copolymer were replaced with 205 parts of a polyvinyl acetateemulsion containing about 55% solids (National Starch 12-k-5l). The basecolor emulsion was stirred, and while under agitation, representativeamounts of the pigment paste of Example 4 were added. The mottled paintproduct did not emulsify in the spray gun in field tests. A satisfactoryspatter coat, completely covering the test area, was obtained with but asingle pass of the spray gun.

The above examples are believed to illustrate fully the practice of theinvention as required; the following examples have been included todemonstrate the scope of the. invention.

'A large number of vehicles or varnishes in production by one of the'worlds largest paint manufacturers for a wide variety of end uses wereselected for their variation in chemical constituency. These varnisheswere tested to determine their HN values or HN requirements. Thefollowing examples illustrate specific ones of said varni'shes whose HNrequirement was determined, the HN value of the varnish solids and theoperability of these viscid hydrophobe materials as the macroscopicphase forming vehicle when substituted for the. ester of Example 2 in aformula similar to Example 3.

Example 13 135' parts of tall oil of an acid refined grade, 68 parts ofblack oil obtained from the alkali refining of linseed oil and 68 partsof Menhadden oil are heated to 370 F. to which and at this lattertemperature 66 parts pentaerythritol and 78 part of litharge are addedand dispersed in the hot oil. Thereafter the temperature is increased to460 F. and held for alcoholysis. When alcoholysis has been substantiallycompleted, cool to 420 F. and add 82 parts of phthalic anhydride.Re-heat to 460 F. and hold under a gentle inert gas blow to an acidvalue of from 1'0-20 and a viscosity of T ('Gardner-Holdt) at 50% solidsin mineral spirits. Cut with 385 parts of mineral spirits. Resultingproduct has an HN value of 54 or between 51 and 52 on the vehicle solidsbasis and is operable as thinned as the macroscopic varnish vehicle ofthe present invention.

Example 14 142 parts of alkali refined soya bean oil, 185 parts of blackoil, 36% parts glycerin and 34% parts of pentaerythritol are heated to400 F. 34 part of litharge is added and the temperature held at 440 F.to completion of alcoholysis. (One hour, more or less.) 154 parts ofphthalic anhydride are added and the varnish pill reheated to 460 R,which temperature is held while the forming varnish is maintained underan inert gas atmosphere andinert gas blow to an acid value of from 15 to19. The varnish pill is reduced with 320 parts of mineral spirits afterthe viscosity of a test portion of vehicle has advanced to Y-Z viscosityat 60% solids when reduced with mineral spirits- The HN requirement ofthe varnish pill, or varnish solids, was 53-54. As the HN requirement ofmineral spirits used as the solvent is 55, there is little differencebetween the HN requirement of the varnish solids and the thinnedvarnish.

Example 15 132 /2 parts of black oil, parts fish oil and 22 parts ofglycerin were heated to 300 F., whereupon A part of litharge and 46%parts pentaerythritol are added and the batch heated to 440 F. foralcoholysis. When alcoholysis has been completed, 126 parts phthalicanhydride are added and the batch heated to 430 F. and held under aninert gas blow and blanket to an acid value of 10-20 and a viscosity ofat 50% solids with mineral spirits. When these conditions have beenreached, the varnish is thinned with 390 parts of mineral spirits. Thesolids ornon-volatile part of this varnish product has an HN number of59. The varnish is illustrative of the critical limitation in the HNvalue for the purposes of this invention. This material is on the veryborderline of operability as the macroscopic particles essential to theends of the invention tend to emulsify in the test latex paint asdescribed in Example 6. All other vehicles having a solids whose HN wasabove 59 and below were inoperable for the purposes of the invention.Comparison is invited between ,thisinoperative varnish with theoperative varnish of Example 14.

Example 16 430 parts of mineral spirits are heated to F. in a kettleequipped with an agitator. To the hot solvent is added 20 parts of rosinand '73 parts of selected gilsonite. After these resins have beendissolved 224 parts of blown Texas asphaltum are added. Agitation iscontinued until the varnish is free from undissolved particles. Theproduct has a body from 70-110 viscosityon a No. 4 Ford cup at 42.5%solids with mineral spirits. The product has an HN number of 26 on 100%solids basis, as near as could be determined. (The intense black colormade accurate determination difiicult.) The product varnish was usefulas the macroscopic disperse phase.

Example 17 parts of dehydrated castor fatty acid are heated to 250 F. atwhich time 85 parts of a glycidyl ether resin having an epoxideequivalent of from 870 to 1025 is added. The temperature is taken to 350F. and 169 parts in addition of the same epoxy resin added to thecontents of the kettle. The temperature is taken to 400 F. and 2 partsof triphenyl phosphite are added. The temperature is increased to 470 F.and the batch held under aninert gas atmosphere with a mild blow for anacid value of 3 maximum. The viscosity is S-W Gardner when thinned to50% solids. When these conditions are met, 406 parts of xylol are usedto thin the batch after it has been appropriately cooled. The HN numberof the solids of this material has been determined to have two values,namely 117 and 52. The second value, determined after a one month test,is believed to be the more accurate value and determination. The varnishwas operable in the invention when tested in accordance with Example 6and 7 procedures.

Example 18 A glycidyl ether resin having an epoxide equivalent of 450 to525 Was obtained from commercial sources. An HN requirement of thevarnish solids material was found at a value of 130 (not rechecked sincethe filing of the parent application). The epoxide resin was useful formacroscopic particle development when tested in the manner of theimmediately prior examples.

held for adduct formation.

1 7 Example 19 777 parts linseed oil and 1.5 parts anthraquinone areheated to 300 F. 70 parts water white rosin and parts fumaric acid arestirred in and the temperature taken to 370 F. After holding one and ahalf hours, 10.5 parts of pentaerythritol are added. The temperature ofthe batch is increased to 450 F. and held for one hour. The temperatureis again increased to 550 F. whereupon an inert gas blow and blanket ismaintained through and over the batch for a 300 second viscosity in aGardner tube. The pill is cooled to 400 F. The Hydrophilic Number of thematerial at 100% solids is 54-55. Operable as macroscopic varnish phaseas tested in the composi- Example 20 85 parts of soya bean oil and 150parts of refined tall oil and 117 parts linoleic acid are heated withparts of malcic anhydride to a temperature of 350 to 400 and 90 parts ofpentaerythritol are added at 400 F. and the temperature returned to 400F. whereupon 103 parts phthalic anhydride are stirred into the reactionmass. The temperature is increased to 475 F. for 3 hours, then to 525 F.for a cure of 100 seconds. The temperature is dropped to 500 F. for a 75second cure, then to 450 F. for a 60 second cure and an acid value ofless than 12 (10-12). 28 parts of polyamide resin (dimer acid-ethylenediamine condensate) are then added and the temperature held at 450 F. toa cure of 50-55 seconds and an acid value of 8-10 or until 1 part ofresin in 9 parts mineral spirits shows no graininess and the solutionhas maximum turbidity. The varnish is then thinned to about 40% solidswith odorless mineral spirits. No HN value could be determined. Theproduct was a gel-like material which prevented handling as in standardvarnishes having less thixotropic quality. The product varnish wasuseful, in fact, very good for the purposes of the invention, however,when used to form the macroscopic disperse phase. (Made in accord withU.S. 2,663,649.)

Example 21 830 parts of China-wood oil and 831 parts of heat bodiedlinseed oil (Z viscosity) are heated to 400 F. in one hour. After thistime 900 parts of cumarone-indene resin are incorporated into the hotoil and the temperature raised to 480 F. This temperature is held for abody of I-K Gardner Holdt at 54% solids with of high flash naphtha at31% mineral spirits. When the stated body has been obtained at thesolids indicated, 2638 parts of the same cumarone-indene resin are addedand the temperature held at 450 F. for a D-F body at 54% solids thinnedwith high flash naphtha. The varnish pill is then dropped into athinning tank and brought to 54% solids with a mixture of high flashnaphtha and mineral spirits at a ratio of 15:30. The hydrophilic numberon the resin solids is 56. The varnish was tested as the. macroscopicphase of the multicolor emulsion paint of this invention, and aspredicted from its HN value operated satisfactorily for the purposes ofthis invention.

The following examples are not fully described as to method ofmanufacture, but are included as illustrative of the lack ofpredictability of varnishes suitable for the present invention basedupon their chemical classification. Usefulness of these varnish vehiclesfor the purpose of the present invention are predictable from their HNrequirement values or numbers.

Example 22 Example 23 A 45% China-wood oil, maleic anhydride modified 13alkyd varnish had an HN requirement of 102. Predicted inoperable. Sofound on test.

Example 24 A 58% soya bean oil alkyd had an HN number of 55- 56 and waspredicted to be operable. So found on test.

Example 25 A 51% soya bean oil-China-wood oil-phenol-aldehyde modifiedalkyd was found to have an HN value of 72. Predicted inoperable. Sofound on test.

Example 26 A 33% linseed-rosin modified alkyd varnish had an HN value of104. Predicted inoperable. So found on test.

Example 28 A 37% dehydrated castor oil alkyd having an HN of 104 waspredicted inoperable. So found on test.

Example 29 A 45% China-wood oil-maleic anhydride modifiedphenolicmodified alkyd had an HN requirement of 82. Predicted inoperative. Sofound on test.

Example 30 A 54% tall oil alkyd had an HN requirement of 63. Upon testthe varnish vehicle was found inoperative for the purposes of thisinvention as the macroscopic disperse phase. This was in accordance withprediction from the HN requirement.

Example 31 A 31% fish oil alkyd modified with 35% styreneinterpolymerized into the alkyd varnish had an HN value of 72. Predictedinoperative. Found inoperative.

Example 32 A 29% lauric acid modified alkyd varnish was found to have anHN value of the solids of 80. Predicted, inoperative: Found,inoperative.

Example 33 A glycidyl ether resin of commerce containing 225 to 290epoxy equivalents (Shell-Epon 834) was found to have an HN of 53.Predicted operative: 'Found operative.

Example 34 Example 35 p A soya fatty acid ester of a glycidyl etherresin had an original HN value after two weeks testing of 114. No HNdetermination was made later. The glycidyl ester varnish was predictedoperable and so found.

(For record purposes, high flash naphtha has an HN of 57; toluene 65;raw linseed oil 43; xylene 56; mineral spirits 55; odorless mineralspirits 47. These values should be useful to the art in making HNcalculations from solvent-thinned varnish solids.)

Example 36 As noted, raw linseed oil has an HN value of 43. Predicted,operable: Found, operable.

' discrete color particles therein in one positions adapted to isExample 37 In the tests described above all the varnishes described wereused to disperse ferrite yellow pigments which bases were incorporatedin test paints where the vehicles were light in color, and dark ironoxide brown to pigment used in the darker colored varnishes. Tests weremade by adding these bases to an emulsion paint product prepared inaccordance with Example 6 and added in the manner of Example 7 and sotested.

Example 38 To demonstrate the universality of the emulsion polymerlatices of commerce which are known to be produced from ethylenicallyunsaturated monomers, a series of purchases of pigmented white latexpaints were made on the open market. Emulsion Latex Paint 1 wasformulated with an acrylic emulsion polymer latex. Emulsion'Latex Paint2 was formulated with a polyvinyl acetate latex emulsion. Latex Paint 3was formulated with a styrenebutadiene latex emulsion. Bases prepared inaccordance with Examples 3 and 4 were added to the commercial latexpaints by slowly stirring in the two colored bases one after the other.The products so produced sprayed out to produce a mottled coating inaccordance with the objects of the invention.

Having described an advance in the art of decorative coatings, what Iclaim as my invention is:

l. A method of preparing a coating composition adapted to sprayapplication to provide a washable solid base color and a plurality ofinterspersed discrete color particles in one pass of a spray gun, whichcomprises dispersing a pigment to form a slurry consisting essentiallyof pigment, water and water soluble protective colloid component,increasing the vehicle binder solids of said aqueous phase by additionthereto of an aqueous emulsion of a polymer prepared by polymerizing anethylenically unsaturated monomer in an aqueous emulsion system theresultant polymer emulsion being capable of depositing a continuous stetfilm, and while slowly stirring said aqueous microscopic dispersion,separately suspending therein macroscopic particle size globules by thediscrete addition to and slow agitation of said aqueous base with apigmented liquid organic resinous varnish containing a non-volatileportion which is characterized by an Hydrophilic Number of about 26-59,the pigment in said varnish being of a color different from that of saidpigment dispersed in said aqueous phase.

2. A method of preparing a coating composition adapted to sprayapplication to provide a washable solid base color and a plurality ofinterspersed macroscopic pass of a spray gun, which comprises dispersinga pigment to form a slurry consisting essentially of pigment, water anda colloidally dispersed water soluble protective colloid component,increasing the vehicle binder solids of said aqueous phase slurry byaddition thereto of an aqueous emulsion of a polymer prepared bypolymerizing an ethylenically unsaturated monomer in an aqueous emulsionsystem said polymeric emulsion system being capable of depositing acontinuous stet film, and while slowly stirring said aqueous microscopicdispersion separately suspending in the thus prepared pigmented latexemulsion paint, particle size globules by the discrete addition of aplurality of difierently colored water insoluble viscid liquid pigmentedorganic resinous varnishes, the non-volatile portion of which varnishesare each characterized by an Hydrophilic Number of about 26-59, andslowly agitating said first microscopic dispersion concurrently withsaid additions. Y

3. The method of preparing multicolor coating comspray application andto provide a washable solid base color and a plurality of interspersedmacroscopic discrete color particles in said coating with one pass of aspray gun which comprises the steps of dispersing a pigment in anaqueous vehicle consisting essentially of water and a water solublealkyl cellulose ether, increasing the binder solids of said pigmentedaqueous phase by addition thereto of an aqueous emulsion of a polymerprepared by polymerizing an 'ethylenically unsaturated monomer in anaqeuous emulsion system said resultant polymer emulsion system beingcapable of depositing a continuous stet film and while slowly stirringsaid aqueous microscopic dispersion separately suspending thereinmacroscopic particle size globules by the discrete addition of aplurality of pigmented water insoluble viscid liquid organic resinousvarnishes, the non-volatile portions of which varnishes are eachcharacterized by an Hydrophilic Number of about 26-59, and slowlyagitating said first microscopic dispersion concurrently with saidadditions, said pigmented varnishes being of color diflerent from eachother and from said pigment dispersed in said aqueous vehicle.

4. A sprayable multicolor oil-in-water emulsion coating compositionwhich comprises in combination a continuous aqueous phase containing aprotective colloid therein and having suspended therein (a) a firstdispersed phase comprising microscopic pigment particles and discretemicroscopic emulsified particles of a polymer prepared by polymerizingan ethylenically unsaturated monomer, said resultant emulsion beingcapable of depositing a stet film upon drying, and

(b) a second dispersed phase comprising macroscopic discrete particlesof a pigmented water-insoluble, viscid, liquid organic resinous varnish,the non-volatile portion of which varnish is characterized by anHydrophilic Number within the range of about 26-59 and -130, saidpigmented varnish having a color diiferent from the pigment of saidfirst dispersed phase.

5. A sprayable multicolor oil-in-Water emulsion coating compositionwhich comprises in combination a continuous aqueous phase containing aprotective colloid therein and having suspended therein (a) a firstdispersed phase comprising microscopic pigment particles and discretemicroscopic particles of a polymer prepared by polymerizing anethylenically unsaturated monomer in an aqueous emulsion system, saidresultant emulsion being capable of depositing a stet film upon drying,and (b) a second dispersed phase comprising macroscopic discreteparticles of a pigmented, water-tnsoluble, viscid, liquid organicresinous varnish, the non-volatile portion of which varnish ischaracterized by an Hydrophilic Number of about 26-59, said pigmentedvarnish differing in color from the pigment of said first dispersedphase.

6. A coating composition of claim 5 in which said protective colloid iscolloidally dispersed in said aqueous phase.

7. The product of claim 5, where the protective colloid is a watersoluble alkyl cellulose ether.

8. The product of claim 7, where the water soluble alkyl cellulose otheris methyl cellulose.

9. The product of claim 7, where the water soluble alkyl cellulose etheris ethyl cellulose.

10. The product of claim 7, where alkyl cellulose other is a watersoluble lulose.

11. The product of claim 7, where the polymer is a copolymer prepared bypolymerizing a mixture of ethylenically unsaturated monomers consistingessentially of a monounsaturated aromatic vinyl compound and aconjugated diolefine, wherein the former is present to an extent of notmore than 67 mol percent and the latter is. present to an extent of notmore than 60 mol percent.

12. The product of claim 11, where the aromatic vinyl compound isstyrene.

a 13. The product of claim 11, where the aromatic viny the water solublemethyl-ethyl celcompound is styrene and the conjugated diolefine isbutadiene.

14. The product of claim 11, where the aromatic vinyl compound is vinyltoluene.

15. The product of claim 7, where the polymer is an acrylate emulsionpolymer.

16. The product of claim 7, wherein the polymer is a vinyl acetatehomopolymer.

17. The product of claim 7, wherein the polymer is a vinyl acetateinterpolymer.

18. The method of claim 2, wherein the alkyl cellulose ether is methylcellulose.

19. The method of claim 2, where the alkyl cellulose ether is a watersoluble ethyl cellulose.

20. The method of claim 2, where the alkyl cellulose ether ismethyl-ethyl cellulose.

21. The method of claim 2, where the alkyl cellulose ether is hydroxyethyl cellulose.

22. The method of claim 2, where the alkyl cellulose ether is an alkalicellulose glycollate.

23. The method of claim 2, where the aqueous emulsion comprises aninterpolymer prepared from a monomeric mixture containing not more thanabout 67 mol percent of a monounsaturated aromatic vinyl compound andnot more than about 60 mol percent of a conjugated diolefine.

24. The method of claim 2, wherein the pigmented liquid organic varnishcomprises the drying oil fatty acid ester of a glycidyl polyether of adihydric phenol free from functional groups other than epoxy andhydroxyl groups having a 1,2 epoxy equivalency greater than one, thenonvolatile portion of said varnish being characterized by anHydrophilic Number of about 26-59.

25. A Water reducible multicolored spray coating composition whichcomprises in combination a continuous aqueous phase containing as theessential Water soluble component an alkyl cellulose ether and aheterogeneous disperse phase; said disperse phase including a polymerprepared by polymerizing an ethylenically unsaturated monomer in anaqueous emulsion system, the resultant emulsion being capable ofdepositing a stet film upon drying, said polymer being in microscopicstate of subdivision, a dispersed pigment of microscopic dimension and amacroscopic suspension of a colored, viscid, liquid hydrophobic dryingoil fatty acid ester pigmented varnish comprising a glycidyl polyetherof a dihydric phenol free from functional groups other than epoxy andhydroxyl groups having a 1,2-epoxy equivalent greater than one, thenon-volatile portion of said varnish being characterized by anHydrophilic Number of about 26-59, the color of said varnish 'beingdifierent from the color of said pigment dispersed in said aqueousphase.

26. The product of claim 25, where the alkyl cellulose ether is methylcellulose.

27. The product of claim 25, where the polymer is a polyvinyl acetate.

28. The product of claim 25, where the mer is a polymeric acrylonitrile.

29. The product of claim 25, where the emulsion polymer contains notmore than 67 mol percent of a monounsaturated aromatic vinyl compoundand not more than mol percent of a conjugated diolefine.

30. A multicolor oil-in-water emulsion coating composition whichcomprises in combinatton an aqueous solution of a protective colloid asthe continuous phase, a first disperse phase comprising microscopicallysuspended pigment particles and particles of a polymer prepared bypolymerizing an ethylenically unsaturated monomer in an aqueous emulsionsystem, the resultant polymer emulsion being capable of depositing astet film upon drying, a second disperse phase comprising macroscopicdiscrete particles of a water-insoluble, viscid, liquid, organic,resinous varnish, the non-volatile portion of which varnish ischaracterized by an I-lydrophilic Number of about 26-59, said varnishbeing pigmented and having a color different from the pigment in saidfirst phase.

emulsion poly- Refcrences Cited in the file of this patent UNITED STATESPATENTS 2,563,991 Damboise Aug. 14, 1951 2,591,904 Zola Apr. 8, 19522,658,002 Schwefsky Nov. 3, 1953 2,709,689 Herzog et a1 May 31, 19552,795,562 Jud June 11, 1957 2,802,799 Johnson Aug. 13, 1957 2,809,119Lesser Oct. 8, 1957 2,811,459 Wittcott et al Oct. 29, 1957 2,828,222Kine Mar. 25, 1958 2,837,444 Hahn June 3, 1958 2,865,871 Johnson Dec.23, 1958

1. A METHOD OF PREPAING A COATING COMPOSITION ADAPTED TP SPRAYAPPLICAYION TO PROVIDE A WASHABLE SOLID BASE COLOR AND PLURALITY OFINTERSPERSED DISCRETE COLOR PARTICLES IN ONE PASS OF A SPRAY GUN, WHICHCOMPRISES DISPERSING A PIGMENT TO FORM A SLURRY CONSISTING ESSENTIALLYOF PIGMENT, WATER AND WATER SOLUBLE PROTECTIVE COLLOID COMPONENT,INCREASING THE VEHICLE BINDER SOLIDS OF SAID AQUEOUS PHASE BY ADDITIONTHEREOF OF AN AQUEOUS EMULSION OF A POLYMER PREPARED BY POLYMERIZING ANETHYLENICALLY UNSATURATED MONOMER IN AN AQUEOUS EMULSION SYSTEM THERESULTANT POLYMER EMULSION BEING CAPABLE OF DEPOSITING A CONTINUOUS STETFILM, AND WHILE SLOWLY STIRRING SAID AQUEOUS MICROSCOPIC DISPERSION,SEPARATELY SUSPENDING THEREIN MACROSCOPIC PARTICLES SIZE GLOBULES BY THEDISCRETE ADDITION TO AND SLOW AGITATION OF SAID AQUEOUS BASE WITH APIGMENTED LIQUID ORGANIC RESINOUS VARNISH CONTAINING A NON-VOLATILEPORTION WHICH IS CHARACTERIZED BY AN HYDROPHILIC NUMBER OF ABOUT 26-59.THE PIGMENT IN SAID VARNISH BEING OF A COLOR DIFFERENT FROM THAT OF SAIDPIGMENT DISPERSED IN SAID AQUEOUS PHASE.